D-Fi Gene Therapy (formerly known as FCX-007) for Dystrophic EB (DEB)

D-Fi Gene Therapy (formerly known as FCX-007) for Dystrophic EB (DEB)

D-Fi

At a Glance

  • A progressive, devastatingly painful and debilitating, genetic blistering disorder that is diagnosed at infancy and often leads to death
  • Prevalence of recessive dystrophic EB (RDEB)—a severe form of DEB1—estimated as ~3,850 patients in the U.S.2
  • Current treatments – including bandaging and antibiotics – only address symptoms
  • First gene therapy to offer the potential to address the underlying cause of DEB by providing functional type VII collagen (COL7) locally to affected areas

About DEB

Dystrophic epidermolysis bullosa (DEB) is one of the four major types of epidermolysis bullosa (EB), a genetic connective tissue disorder that causes the skin to be extremely fragile. DEB results from mutations in the type VII collagen gene, or COL7A1, which encodes COL7. COL7—a protein—is the main component of anchoring fibrils, which anchor the basement membrane zone of the epidermis to the dermis, providing structural integrity to the skin at the dermal-epidermal junction. When functional COL7 is deficient, the anchoring fibrils cannot form properly.  Without these fibrils, skin layers separate causing blisters and wounds to form in response to any kind of friction or trauma, like rubbing or scratching. In mild cases—dominant dystrophic epidermolysis bullosa (DDEB)—blistering may be limited to the hands, feet, knees and elbows, while more severe cases—recessive dystrophic epidermolysis bullosa (RDEB)—have widespread blistering and areas of missing skin often present at birth. 

Recessive dystrophic epidermolysis bullosa (RDEB)—a severe form of DEB—is a progressive, devastatingly painful and debilitating disorder. RDEB is an autosomal recessive disorder, meaning that a child has inherited copies of the defective gene from both parents3. Patients with RDEB typically show signs and symptoms shortly after birth and are diagnosed as newborns due to the severity of the disease. RDEB patients have the highest rate of morbidity and mortality of all genetic blistering disorders

Dominant dystrophic epidermolysis bullosa (DDEB) patients typically have higher levels of COL7A1 expression, resulting in milder signs and symptoms, with blistering often limited to the hands, feet, knees and elbows with mild scarring. Nevertheless, untreated symptoms may lead to serious complications, which could be fatal.

Presently, there is no cure or U.S. Food and Drug Administration approved treatments for RDEB or DDEB and treatment is generally limited to supportive care.
  

About D-Fi

D-Fi (dabocemagene autoficel, formerly known as FCX-007), is being developed as a disease-modifying, autologous cell-based gene therapy to address the deficiency of functional type VII collagen protein (COL7) in patients with autosomally recessive or dominant dystrophic epidermolysis bullosa, or DEB. D-Fi is comprised of autologously-derived dermal fibroblasts genetically modified with a lentiviral vector containing the COL7A1 gene, to express COL7. D-Fi is locally administered by injection directly into the papillary dermis of wounds of DEB where the COL7 protein can support the formation of anchoring fibrils in the skin, thereby avoiding systemic treatment.

The U. S. Food and Drug Administration has granted Orphan Drug designation to D-Fi for the treatment of Dystrophic Epidermolysis Bullosa, which includes RDEB. In addition, D-Fi has been granted Rare Pediatric Disease designation, Fast Track designation and Regenerative Medicine Advanced Therapy (RMAT) designation by the FDA for treatment of RDEB.

How Does D-Fi Gene Therapy Work?

Dermal fibroblasts are collected from the patient, cultured and genetically modified to provide functional COL7 and then injected locally into the affected areas. 

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  1. The Dystrophic Epidermolysis Bullosa Research Association of America. EB in Depth. https://www.debra.org/about-eb/eb-depth. Accessed July 2020
  2. Based on claims data analysis.
  3. Stanford Medicine, Epidermolysis Bullosa Clinic Frequently Asked Questions